Grinding-rest for use in grinding mowing-machine knives and the like.



W. RAWLINSON.

GRINDING BEST FOR USE IN GRINDING MOWING MACHINE KNIVES AND THE LIKE.

A-PPLIUATION FILED MAR. 11, 1909.

956,41 6. V Patented Apr. 26, 1910.

3 QHBBTB-SHEET 1.

W. RAWLINSON. GRINDING BEST FOR USE IN GRINDING MDWING MACHINE KNIVESAND THE LIKE.

, APPLICATION FILED MAR. 11, 1909. 956,41 6.

Patented A131. 26, 1910.

s SHEETS-SHEET 2.

ANDREW a. GRANAM c0. PNOYD-LITNOGRAPNERS. WASHINGTON, o. c.

W. RAWLINSON.

GRINDING BEST FOR USE IN GRINDING MOWING MACHINE KNIVES AND THE LIKE.APPLIGATION FILED MAR.11, 1909.

956,41 6. Patented Apr. 26, 1910. $9. a SHEETS-SHEET 3.

ANDREW a GRAHAM cm PMOw-LIYROGRAPHERS, WASHINGTON. D a

siren s'rnrns PATENT OFFI WILLIAM RAWLINSON, OF EAST HAM, ENGLAND.

GRINDING-REST FOR USE IN GRINDING MOWING-MACI-IINE KNIVES AND THE LIKE.

Specification of Letters Patent.

Patented Apr. 26, 1910.

Application filed March 11, 1909. Serial N 0. 482,801.

T 0 all whom it may concern:

Be it known that I, WILLIAM RAWLINsoN, subject of the King of the UnitedKingdom of Great Britain and .Ireland, residing at 87 Rutland road, EastHam, in the county of Essex, England, have invented certain new anduseful Improvements in Grinding-Rests for Use in Grinding Mowing-MachineKnives and the Like, of which the following is a specification,reference being had therein to the accompanying drawings.

This invention relates to a new or improved grinding rest which, whileespecially suitable for use in supporting mowing machine knives duringgrinding, may be found serviceable in the grinding of other blades thelength of which is considerable in proportion to the breadth of thegrindstone; and the invention has for its main object to facilitate thetraverse of the blades over the grindstone for the purpose of grindingthe successive edges or edge portions.

Now in a grinding rest according to this invention there are providedfor the support of the knife arms that are mounted on a shaft or barthat can slide in a frame adapted to be attached to the support in whichthe grindstone is mounted. The knife is supported and clamped in slotsarranged in these arms; its edges or edge portions can then be broughtsuccessively into contact with the grindstone by sliding the shaft alongin its bearings, the need for sliding the knife in the rest or forunclamping it being thus avoided.

The accompanying drawings show an example of grinding rest according tothis invention in its application to the grinding of a mowing machineknife; where1n Figures 1 and 2 are respectively front and sideelevations, Fig. 3 is a plan, Fig. 4: is a central transverse section,Fig. 4 is a perspective view illustrating the supporting bracket, Fig. 5is a side view of the bar-supporting frame illustrating certain detailmodifications; and Fig. 6 is an enlarged side view of one of theknife-supporting arms.

The arms 1, which support the knife 2 are adjustably mounted on a shaftor bar .3 to which they can be clamped, as by thumbscrews 4:. The lengthof the bar 3 may be varied in accordance with the length of the knifeand the said bar 3 is mounted in projections 11 which extend outwardlyfrom arms 11 of a bracket 11". The bracket 11 is arranged between theextensions 5 of a frame 6, the said extensions 5 being provided withopenings in which are arranged the projections 11 These latter arecapable of shifting within the extensions 5. The openings through theprojections 11 are squared, the shaft 3 also being squared and by suchan arrangement the shaft 3 can slide in the longitudinal direction inthe projections 11 but when the arms 11 are shifted, the shaft 3 iscarried therewith. The knife 2 is supported in slots 7 formed in thearms 1 and clamped in position by the screws 8. The edges of the knifesections 9 can thus be brought successivelyinto contact with thegrindstone 10 by sliding the bar 3 in the projections 11 These latterconstitute bearings for the bar.

In the arrangement shown in Figs. 1 to 4: the bracket 11 is providedwith a lateral extension 12 forming a stiff spring blade, against whichthere bears a set-screw 13 screwed into the frame 6, this set-screwserving to adjust the position of the arms 1 and the knife in relationto the surface of the grindstone, so that the knife is held near orpressing lightly against the stone, grinding pressure being applied toit by hand. The frame 6 is hinged to a base 14 that can be bolted orclamped to the grindstone support 15.

On the frame 6 there is provided a setscrew 16 that bearsagainst a stop17 on the base 14 and that can be adjusted so as to limit the depth towhich the knife-sections can be ground.

There is provided between the frame 6 and the base let a spring 18 thatis supported on a stud 19 on the base, and the compression of which canbe adjusted by a screw 20, this spring serving automatically to applythe desired grinding pressure.

In the modified construction shown in Fig. 5 the portion 12 of thebracket 11 is rigid, and there is passed through this portion andthrough the bridge 21 of the frame 6 a screw-bolt 22 furnished with abutterfly-nut 23 for adjusting the compression of a spring 24 thatautomatically applies grinding pressure to the knife.

The slots 7 are'preferably formed with extensions 25 that provide roomfor the passage of the heads 26 of the knife 2, these extensionsallowing the knife blades or sections to be ground to the end of theknife, or close up to the heads 26.

In the example of apparatus shown two arms 1 are provided for thesupport of the knife; obviously, however, for short knives a single armmay sufiice while for exceptionally long knives, more than two arms maybe provided; while for the sliding shaft or bar a sliding knife supportof another form may in some cases be substituted.

What I claim is l. A grinding rest comprising a frame, a longitudinallymovable bar, a shiftable supporting means for said bar extending in saidframe, adjustable knife carrying arms connected to said bar and support,means for pivoting the frame to the support, an adjustable stop forlimiting the movement of the frame, and a cushioning means interposedbetween the frame and its support.

2. A grinding rest, a longitudinally movable bar, a spring-controlledshiftable supporting means for the bar, and knife carrying armsadjustably connected to said bar and formed with slots for the receptionof the knife, said slots having extensions for the passage of the headsof the knife.

3. A grinding rest comprising a springcontrolled pivoted frame, alongitudinally movable bar, a spring-controlled supporting means forsaid bar, said supporting means mounted in said frame and capable ofturning therein, whereby the bar will be turned, and knife-carrying armsconnected to the bar.

4:. A grinding rest comprising a springcontrolled pivoted frame, alongitudinally movable bar, a spring-controlled supporting means forsaid bar, said supporting means mounted in said frame and capable ofturning therein, whereby the bar will be turned, and knife-carrying armsconnected to the bar, said arms provided with slots for the reception ofthe knife, said slots having extensions to provide clearances for thepas sage of the heads of the knife.

In testimony whereof I aflix my signature in the presence of twowitnesses.

S. F. PAUL.

